Food Chemistry
Hamed Saberian; Vahid Pasban
Abstract
[1]Introduction: Anthocyanins are one of the most important of food colorants, which are found in many fruits, flowers, and vegetables, and have been used as natural pigments in commercial foods and beverage products due to their desirable colors and potential nutritional benefits. Saffron (Crocus sativus) ...
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[1]Introduction: Anthocyanins are one of the most important of food colorants, which are found in many fruits, flowers, and vegetables, and have been used as natural pigments in commercial foods and beverage products due to their desirable colors and potential nutritional benefits. Saffron (Crocus sativus) is the most expensive spice of the world and an average 86.4% of wet weight or 96.4% of dry weight of saffron flowers is related to petals. Saffron petals usually do not have a commercial value but contain large amounts of anthocyanins, flavonoids and glycosides. Thus, these petals can be a good source of natural dyes applicable in pharmaceuticals, confectionery, and soft drinks. However, anthocyanins are readily unstable compounds with exposure to oxygen, pH, temperature, enzyme, light, as well as surrounding components, which reduces food color and quality. Losses of anthocyanins occur during juice processing and storage, and methods are needed to prevent these losses. Up to now, various methods including the encapsulation and the co-pigmentation have been tried to intensify the stability of anthocyanins. The co-pigmentation based on the molecular interactions, has been shown to be an efficient way to stabilize anthocyanins. The addition of organic acids, flavonoids, alkaloids, polysaccharides, proteins, etc. as a co-pigment, can improve the stability, and change the bioactivity of anthocyanins. Encapsulation of anthocyanins by alpha and beta cyclodextrins is a potential treatment that could d anthocyanin losses. Anthocyanins can form inclusion complexes with cyclodextrin molecules, which may protect anthocyanins from hydration and polymerization reactions. Therefore, saffron petal is a potential resource of anthocyanin in Iran. Low thermal stability of the anthocyanins caused a tendency to the synthetic colorants. Therefore, the main goal of this research was to investigate the effect of cyclodextrins and co-pigmentation on the anthocyanin extract of saffron petal during heat treatment. Materials and Methods: Anthocyanin extract of saffron petal was extracted by 50% acidic ethanol solution at ambient temperature. Acidified extract was concentrated by a rotary evaporator at 40˚C up to 9 percent concentration of solid materials. Different concentrations of alpha and beta cyclodextrin (10, 25, 50, 75 and 100 mole alpha or beta cyclodextrin to one mole anthocyanin) and also, different co-pigments such as gallic acid (at two molar ratio of 50:1 and 100:1of galic acid/anthocyanin), ferulic acid (at two molar ratio of 50:1 and 100:1of ferulic acid/anthocyanin), quercetin (at two molar ratio of 2.5:1 and 5:1 of quercetin/anthocyanin) and rutin (at two molar ratio of 10:1 and 25:1 of rutin/anthocyanin) were used to study the thermal stability of anthocyanin. Furthermore, the hydroalcoholic extract of rosehip was prepared and concentrated thereby, the rosehip extract (at two molar ratio of 50:1 and 100:1gallic acid equivalent/anthocyanin) was used as a co-pigment. Total anthocyanin content was measured using differential pH method and reported based on mg of cyanidin 3-glucoside per 100 ml the model drink. a* value was measured by Hunter Lab. Model drink (20 mM acid citric buffer in pH of 3) containing 0.01 % CaCl2 and anthocyanin extract was prepared. Prepared model drinks were heated at 90 °C during 0, 15, 30, 45, 60, 90 and 120 min and then, were cooled up to room temperature. Half time of anthocyanin was calculated and the mentioned treatments were investigated to evaluate the stability of the different compounds. Results and Discussion: The results indicated that alpha cyclodextrin at molar ratio of 50:1 (alpha cyclodextrin to anthocyanin) hadn’t any significant effect on the anthocyanin stability but beta cyclodextrin at molar ratio of 50:1 increased the colorant stability, which can be due to the smaller cavity of alpha cyclodextrin rather than beta cyclodextrin that lead to the lower interaction between alpha cyclodextrin and anthocyanin. Although, phenolic co-pigments hadn’t any significant effect on the anthocyanin stability of the model drink but the rosehip extract at two molar ratios of 50:1 and 100: 1 increased the anthocyanin retention. Total phenolic content of rosehip extract was 14.56 g gallic acid equivalent per liter of the extract and total flavonoid content was 365 mg quercetin equivalent per liter of the extract. According to the studies and our results about total phenol and flavonoid content, the increased retention of the anthocyanin can be related to the variety of the phenolic and flavonoid compounds of the rosehip extract. Therefore, beta cyclodextrin as a trapping agent and rosehip extract as a co-pigment, can increase the anthocyanin stability of the saffron petal during heat treatment.
Sharareh Rezaeian; Hamid Reza Pourianfar; Shadi Bolourian; Hamed Saberian
Abstract
Introduction: At the present, culinary-medicinal mushroom Enoki, Flammulina velutipes, ranks fifth among cultivated mushrooms in the world. Enoki has a delightfully crunchy texture and desirable taste. In addition, research has proved that this mushroom possesses substantial nutritional and medicinal ...
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Introduction: At the present, culinary-medicinal mushroom Enoki, Flammulina velutipes, ranks fifth among cultivated mushrooms in the world. Enoki has a delightfully crunchy texture and desirable taste. In addition, research has proved that this mushroom possesses substantial nutritional and medicinal properties. However, commercialization of Enoki is not yet expanded worldwide and it is still largely behind the other major edible mushrooms in some countries in west Asia (such as Iran). Based on our recent successful study on cultivation of Enoki in locally available lignocellulosic substrates, this study was aimed to evaluate the possibility of production of a novel functional drink based on Enoki mushroom supplemented with curcumin. Materials and Methods: A pure culture of the cultivated strain of Enoki was freshly fructified in a locally available lignocellulosic substrate composed of 40 % wheat straw + 40 % sawdust + 18 % wheat bran + 1 % lime + 1 % gypsum. The fresh fruiting bodies were crushed to different forms of pulp and puree to be utilized in the basic formulation of drink. Then, different concentrations of mushroom particles (5, 7.5 and 10 %) and pectin gum (0.05, 0.075 and 0.10 %) were used. Following pasteurization at 90 ºC for one minute, the rheological and sensory characteristics of the drink were evaluated. The viscosity and the flow behavior of the samples were measured at 7°C. A rotational programmable viscometer (LVDV-II Pro, Brookfield Engineering Inc., USA) with an LV spindle was employed. About 25 ml of each drink was poured into the cylinder of the viscometer and shear rate was measured from 5 to 200 s−1 within 5 s intervals. Effect of different treatments (pectin gum and mushroom concentration) on color indices of the Enoki drink was studied using colorimeter (ColorFlex EZ, Hunter Lab, USA) and indices of, L* (brightness), a* (redness–greenness), b* (yellowness–blueness), were determined. Some sensory characteristics (taste, odor, color, mouth feel, consistency, particle concentration and overall acceptance) of the Enoki drinks were evaluated by 12 trained panelists (aged 25–50 years) using a 5 level hedonic test (1, 2, 3, 4 and 5) from left to right representing unacceptable, relatively acceptable, good, very good, and excellent. Three types of flavor (Lime, tropical fruits and apple) were employed and the effect of the flavors on odor, flavor, taste and overall acceptance of the pulp- based drink was investigated. Finally, three concentrations of curcumin (0.01, 0.03 and 0.05 %), as a natural colorant, were used in the pulp- based drink and the overall acceptance of the panelists was evaluated in a separate test. Factorial tests based on the completely randomized design was employed to evaluate the effect of different concentration of mushroom and pectin gum. Results were analyzed by analysis of variance (ANOVA) using SPSS 19 statistical software and the Duncan’s test with 95% confidence interval was used to compare the means of the tests. The results which were presented in this research have been obtained from the average values of 12 replicates. Results and Discussion: Rheological tests showed that the flow behavior of the drink was pseudoplastic (or shear thinning), which indicated that the viscosity was decreased when the shear rate increased. All the samples had a yield stress at 7°C. Therefore, all the drink samples had a jelly form before exerting any stress, while the mushroom particles were completely suspended in the drink. From the panelists’ point of view, there was not any difference between the color of the drink containing different gum and mushroom, but L*, a* and b* values were significantly different. By increasing of the gum and mushroom concentration, brightness index (L*) increased. Sensory tests indicated that the highest and the lowest scores of flavor were related to samples containing 5 and 10 % (w/w) mushroom, respectively (p<0.05). Finally, the drink containing 5% mushroom puree and 0.05 % pectin gum was selected. The results of sensory evaluation showed that the drink containing mushroom pulp was significantly better than one containing mushroom puree (p<0.05). The overall acceptance of the Enoki drink containing lime flavor was the highest and there were not any significant differences between those containing apple and tropical fruits flavor. Furthermore, sensory acceptance of the drink increased by adding 0.05 % curcumin into it. It can be concluded that the drink containing Enoki mushroom pulp may have a good potential to be accepted by consumers. The use of a culinary-medicinal mushroom such as Enoki along with a natural colorant (curcumin) may make the drink a functional food without having any side effect. Overall, the findings of this study showed that the industrial production of this novel functional drink, with acidic lime taste and curcumin colorant, is feasible from a technical point of view.
Hamed Saberian; Zohreh Hamidi-Esfahani; Hassan Ahmadi Gavghili; Mohsen Barzegar
Abstract
Introduction: Ohmic heating or direct resistance heating is one of the several electromagnetic based methods, occurs when alternating electrical current is passed through a conductive material, with the primary purpose of heating it due to the electrical resistance of the foods. There are many applications ...
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Introduction: Ohmic heating or direct resistance heating is one of the several electromagnetic based methods, occurs when alternating electrical current is passed through a conductive material, with the primary purpose of heating it due to the electrical resistance of the foods. There are many applications that can use ohmic treatment technology, such as blanching, evaporation, dehydration, fermentation, extraction, sterilization and pasteurization of foods (Saberian et al. 2015; Assiry et al. 2010). Pectins are complex heteropolysaccharides, consisting of α-1, 4-linked D-galacturonic acid units and interrupted by L-rhamnose residues with side chains of neutral sugars, mainly L-rhamnose, L-arabinose and D-galactose. In the industrial extraction process, pectin is usually extracted from waste plant material such as citrus peels, apple pomace, sugar beet pulp and sunflower head using hot water (60–100°C) acidified with a mineral acid (such as sulfuric, phosphoric, nitric, hydrochloric) or organic acid (especially citric acid) within the pH of 1.5–3 for 0.5–6 h. The aim of this study was to explore the effect of enzymatic extraction on the yield and quality properties (degree of esterification, Galacturonic acid, emulsifying properties and viscosity) of the pectin, and to compare this pectin with the pectins extracted by ohmic and conventional methods. Finally, the best extraction method was selected.
Materials and Methods: Extraction of pectin was done with the assistance of an ohmic heating system at working frequency of 50 Hz under different parameters including voltage gradient (7-15 V/cm), temperature (50-90°C), and time (5-30 min). Then, the effect of enzyme dose (0-20% v/w) of Celluclast and Rohament CL, solid/liquid ratio (S/L ratio) (1:10 to 1:50 g/ml) and extraction time (1-18 h) on the yield of the extracted pectin from orange waste was investigated.
After the time of extraction (enzymatically, ohmically or conventionally), the sample was cooled to room temperature and centrifuged (10000 rpm, 15 min), and the supernatant was precipitated with two volumes of 96% (v/v) ethanol at 4 °C for 1 h. The precipitated pectin mass was washed twice with 96% ethanol in order to remove impurities. The pectin was dried in a forced circulation oven at 55°C until a constant weight (14 h).
Galacturonic acid content was determined according to Scott (1979) with some modifications. The degree of esterification (DE) of pectin samples was determined by titrimetric method according to Santos et al. (2013).
Emulsifying activity and emulsion stability were measured according to the method described by Yapo et al. (2007).
The viscosity and the flow behavior of the selected pectin solutions (2%, w/v) extracted conventionally and ohmically at 90°C for 30 min (the optimum extraction condition) and the highest pectins extracted enzymatically, were measured at 25°C.
Pectin powder samples were mixed with KBr and pressed into KBr pellets before FTIR analysis. PerkinElmer FTIR spectra (PerkinElmer, Frontier model, USA) was applied at the transmission mode in the frequency range of 4000–400 cm-1 at a resolution of 1 cm-1.
Results were analyzed by analysis of variance (ANOVA) using SPSS 19 statistical software and the Duncan’s test with 95% confidence interval was used to compare the means of the tests. The results which were presented in this research, have been obtained from the average values of the minimal two replicate experiments.
Results and Discussion: first, the effect of enzyme dose, solid/liquid ratio (S/L ratio) and time of extraction on the yield of the extracted pectin from orange waste by using Celluclast and Rohament CL enzymes was studied. Then, the yield, of esterification, galacturonic acid, emulsifying properties and viscosity behavior of the pectins extracted in the optimum condition by enzymes were compared to the extracted pectins by ohmic and conventional methods. Results indicated that the highest yield of pectin was obtained by using Celluclast and Rohament CL enzymes at enzyme doses of 15 and 17.5%, S/L ratio of 1:20 and 1:40 (g/ml) and time of 3 h for both, which were 5.92 and 10.70 %, respectively. The highest yield of pectin by ohmic heating was obtained at the voltage gradient of 15 v/cm, the temperature of 90°C during 30 min (14.33%), which was higher than the amount obtained by conventional method (13.53%) may be due to the electroporation (disruptive pores which were made on the cell membrane by the electric field) (Cho et al., 1996). de Oliveira et al. (2015) reported that the moderate electric field (at 45°C, 50 and 100 V) extracted the pectin significantly (p < 0.05) more than the conventional extraction. The emulsifying activity of the extracted pectins by ohmic and conventional methods were 65.47 and 67.18%, respectively, although the pectins extracted by enzymatic method had not any emulsifying activity. It seems that during the pectin extraction, enzymes hydrolyzate the pectins. The viscosity of the pectins extracted by ohmic and conventional methods at the concentration of 2% was higher than those obtained from the enzymatic method. Therefore, pectin extracted by ohmic and conventional methods had the highest yield, emulsifying properties, and viscosity.
